Green Invasion: Destroying Livelihoods in Africa [Video]

CABI, together with Tmax Productions, have produced a video called the ‘Green Invasion – Destroying Livelihoods in Africa.” The short film (approx. 7mins long) details how invasive weeds are impacting on the lives of rural communities in East Africa.

Although a large number of non-native species have become invasive in the region, this film focusses on four of the most problematic species namely Chromolaena odorata (Devil weed), Parthenium hysterophorus (famine weed), Prosopis juliflora (Mathenge) and Opuntia stricta (erect prickly pear). The excellent footage shows the extent of  weed infestations with accounts from community members on how these invasive plants are destroying the natural resource base on which they depend. It is clear that invasive weeds are destroying traditions, cultures and a way of life for millions of people on the continent.

However, all is not lost. The film notes that if effective management programmes are implemented, including biological control, we can make a difference to many people’s lives.

Although of general interest, the film is intended to raise the profile of invasive species and their impacts on livelihoods amongst donors and governments. We need them to take action and provide support for initiatives to manage one of the biggest threats to economic development on the planet.

Arne Witt
CABI Regional Coordinator, Invasives (Africa & Asia)
@WittArne


New in February 2014 from the ISC

In February 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Drosophila suzukii - The damage caused by D. suzukii larvae renders fruit unmarketable. In 2008 economic losses (based on maximum reported yield losses) for California, Oregon and Washington were estimated at 40% for blueberries, 50% for caneberries, 33% for cherries and 20% for strawberries. Production in these three states could sustain $511 million in damages annually because of D. suzukii. D. suzukii produces up to five times more hemocytes than D. melanogaster, making it significantly more resistant to wasp parasitism and making it less likely for indigenous specialized parasitoids to shift host onto it.

Drosophila suzukii ISC datasheet

Drosophila suzukii Invasive Species Compendium datasheet

Rattus rattus - R. rattus has directly caused or contributed to the extinction of many species of wildlife including birds, small mammals, reptiles, invertebrates and plants, especially on islands. The primary economic impact of R. rattus relates to agricultural and horticultural damage. It is capable of destroying up to 30% of crops annually. Phylogenetic restructuring of the ‘Rattus rattus complex’ (comprising the oceanic and Asian groups) is on-going. Based on molecular evidence, there are multiple species within what has historically been identified as Rattus rattus.

Leonurus japonicus - L. japonicus is a highly invasive weed widely naturalized in tropical and subtropical ecosystems. It commonly grows as a weed in waste places, disturbed sites and along roadsides and as an ornamental in gardens and yards. L. japonicus also invades pastures and arable land as well as coastal and dry forests. In a recent work, Xiong, et al. (2013) described the chemical composition and the antibacterial activity of essential oils from different parts of L. japonicus. These essential oils showed antibacterial activity against various Gram-positive bacteria.

Other invasive species datasheets recently published include…

Chamaecrista nictitans

Medicago polymorpha

Pantherophis guttatus

Amphisbaena fuliginosa

Datura ferox

Schilbe mystus

Protopterus aethiopicus

Horizon Scanning for Invasive Species

In this, the era of globalisation, increases in international trade, transport and travel have driven an upsurge in the diversity and volume of non-native species introductions to new areas worldwide. Introduced plant, animal and pathogen species may fail to establish in a new range, and where they do establish, may be environmentally benign. However, there is potential for introduced non-native species to become invasive, even after a (sometimes extensive) period of time without apparent negative impacts.

Preventing the introduction and establishment of a species considered to be an invasion risk is key to mitigating its potential impacts in a new area. For this to be done effectively, it is vitally important that countries conduct horizon scanning initiatives to determine the non-native species likely to arrive, to evaluate the threat posed should the organism become established, to determine by which pathway(s) the organism may be introduced and where appropriate, to convey to the competent authority the requirement for rapid response strategies to alert list species. The recent European Union (EU) draft regulation which aims to legislate for the control of invasive non-native species in the EU is likely to be focused on a list of priority non-native species. A significant number of the species on this list are likely to be alert species not yet present in the region, but which will be determined as threats through the horizon scanning and prioritisation process. The outcomes of this horizon scanning process are likely to be of great interest and importance to various concerned parties across the European continent and beyond, and will certainly be subject to close scrutiny.

Horizon -  Norma Desmond, Flickr

Are invasive species on the horizon?
Photo: Norma Desmond, Flickr

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Himalayan Balsam and its impact on UK invertebrates

Himalayan Balsam and its impact on UK Invertebrates - Infographic

Himalayan balsam is one of the UK’s most widespread invasive weed species, colonising river banks, wasteland, damp woodlands, roadways and railways. Research by CABI scientists has shown local invertebrate biodiversity is negatively affected by the presence of Himalayan balsam. This leads to fragmented, destabilised ecosystems, which has serious consequences on processes and functioning, and complicates habitat restoration unless remedial actions are implemented.

Tanner, R.A., Varia, S., Eschen, R., Wood, S., Murphy, S.T. & Gange, A.C. (2013) Impacts of an invasive non-native annual weed, Impatiens glandulifera, on above- and below-ground invertebrate communities in the United Kingdom. PLoS ONE, 8(6): 1-13

Lakes poisoned to halt topmouth gudgeon invasion

Several lakes in Hampshire are being poisoned in a bid to control topmouth gudgeon (Pseudorasbora parva), an invasive non-native fish first introduced to Britain in the 1980s which has become more widespread in recent years.

Topmouth gudgeon (Pseudorasbora parva)

Topmouth gudgeon (Pseudorasbora parva)
(Photo credit: Melania, Wikimedia Commons)

The fish, native to Asia, has spread across much of Europe in recent decades, travelling along waterways and facilitated by illegal fish stocking. Its impacts are significant and include predation on native and farmed fish eggs, resource competition and the ability to host and transmit the rosette agent (Sphaerothecum destruens), a fish parasite that is particularly devastating to Salmonid species such as trout and salmon

The piscicide, Rotenone, is to be applied to the lakes following the removal of native fish in an effort to eradicate topmouth gudgeon whilst limiting non-target impacts. The method has been used by the Environment Agency at a number of sites over the last decade as part of a wider strategy to eradicate topmouth gudgeon from England and Wales. Rotenone breaks down over several weeks, after which the site can be re-stocked with native and/or farmed fish species. Whilst the intervention is fairly drastic, it is considered necessary to prevent the further spread of topmouth gudgeon and limit its likely environmental and economic impacts.

Find out more about the topmouth gudgeon and hundreds of other invasive species at CABI’s open access Invasive Species Compendium.


Dr Paul Fisher
Communications Manager, CABI

The urgent need for evidence based policy in invasive species management

Hundreds of invasive species experts gathered last week, 23-27 October, in Qingdao China at the 2nd International Congress on Biological Invasions. High on the agenda was how policy makers can respond to the accelerating risk posed by invasive species as international trade increases and climate change opens up new opportunities for invasion.

Prof. Daniel Simberloff speaking at the ICBI plenary session

Prof. Daniel Simberloff speaking at the ICBI plenary session (Photo Credit: CABI)

In a session chaired by Prof. Daniel Simberloff on ‘Approaches in the International Policy Arena’, CABI was given the key note speaker position to showcase the contribution that systematic reviews can make in converting scientific evidence into practical evidence-based policy.

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Weevil fight them on the waterbodies

Introduced to Britain in the 1980s through the aquatic trade Hydrocotyle ranunculoides, commonly known as floating pennywort, is rapidly spreading through Europe and particularly in the UK, Belgium, Germany, Italy, France and the Netherlands. Originating in Central and South America, this stoloniferous perennial plant is forming dense, impenetrable mats which rapidly dominate water bodies, outcompeting and displacing native species and compromising flood defences, navigation and leisure activities.  Despite its relatively recent introduction, establishment and spread have been exponential thanks largely to its extremely fast growth rate (up to 20cm per day) and its ability to re-generate from small fragments. In 2010, floating pennywort was added to section 14, schedule 9 of the UK’s Wildlife and Countryside Act 1981.  A recent report estimates its cost to Great Britain’s economy as £25.5 million each year through management, disposal, flooding and indirect costs to boating and angling.  News that from 2014 the sale of this plant will be banned is significant and welcomed.

Left - A sheep in a UK river clogged with Hydrocotyle (Credit: Trevor Renals); Right - Distribution map of floating pennywort invasion (Credit: DAISIE)

Left – A sheep in a UK river clogged with Hydrocotyle (Credit: Trevor Renals, Environment Agency)
Right – Distribution map of floating pennywort invasion (Credit: DAISIE)

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